Develop Reference

Trying to remove multiple space in txt file using python [duplicate]

So I have this crazy long text file made by my crawler and it for some reason added some spaces inbetween the links, like this:
https://example.com/asdf.html (note the spaces)
https://example.com/johndoe.php (again)
I want to get rid of that, but keep the new line. Keep in mind that the text file is 4.000+ lines long. I tried to do it myself but figured that I have no idea how to loop through new lines in files.

Seems like you can't directly edit a python file, so here is my suggestion:
# first get all lines from file
with open('file.txt', 'r') as f:
lines = f.readlines()
# remove spaces
lines = [line.replace(' ', '') for line in lines]
# finally, write lines in the file
with open('file.txt', 'w') as f:
f.writelines(lines)

You can open file and read line by line and remove white space -
Python 3.x:
with open('filename') as f:
for line in f:
print(line.strip())
Python 2.x:
with open('filename') as f:
for line in f:
print line.strip()
It will remove space from each line and print it.
Hope it helps!

Read text from file, remove spaces, write text to file:
with open('file.txt', 'r') as f:
txt = f.read().replace(' ', '')
with open('file.txt', 'w') as f:
f.write(txt)
In #Leonardo Chirivì's solution it's unnecessary to create a list to store file contents when a string is sufficient and more memory efficient. The .replace(' ', '') operation is only called once on the string, which is more efficient than iterating through a list performing replace for each line individually.
To avoid opening the file twice:
with open('file.txt', 'r+') as f:
txt = f.read().replace(' ', '')
f.seek(0)
f.write(txt)
f.truncate()
It would be more efficient to only open the file once. This requires moving the file pointer back to the start of the file after reading, as well as truncating any possibly remaining content left over after you write back to the file. A drawback to this solution however is that is not as easily readable.

I had something similar that I'd been dealing with.
This is what worked for me (Note: This converts from 2+ spaces into a comma, but if you read below the code block, I explain how you can get rid of ALL whitespaces):
import re
# read the file
with open('C:\\path\\to\\test_file.txt') as f:
read_file = f.read()
print(type(read_file)) # to confirm that it's a string
read_file = re.sub(r'\s{2,}', ',', read_file) # find/convert 2+ whitespace into ','
# write the file
with open('C:\\path\\to\\test_file.txt', 'w') as f:
f.writelines('read_file')
This helped me then send the updated data to a CSV, which suited my need, but it can help for you as well, so instead of converting it to a comma (','), you can convert it to an empty string (''), and then [or] use a read_file.replace(' ', '') method if you don't need any whitespaces at all.

Lets not forget about adding back the \n to go to the next row.
The complete function would be :
with open(str_path, 'r') as file :
str_lines = file.readlines()
# remove spaces
if bl_right is True:
str_lines = [line.rstrip() + '\n' for line in str_lines]
elif bl_left is True:
str_lines = [line.lstrip() + '\n' for line in str_lines]
else:
str_lines = [line.strip() + '\n' for line in str_lines]
# Write the file out again
with open(str_path, 'w') as file:
file.writelines(str_lines)

Python - Remove all the lines starting with word/string present in a list

I am trying to parse huge 50K lined file in which I have to remove any line that starts with the word present in a predefined list.
Currently I have tried the below and the output file (DB12_NEW) is not working as desired -
rem = ['remove', 'remove1', 'remove2'....., 'removen']
inputFile = open(r"C:\file", "r")
outputFile = open(r"C:\file_12", "w")
lines = inputFile.readlines()
inputFile.close()
for line in lines:
for i in rem:
if line.startswith(i):
outputFile.write('\n')
else:
outputFile.write(line)
I am getting the same file as output that I initially put in... the script is not removing the lines that start with any of the strings present in the list.
Can you please help understand how to achieve this?

Use a tuple instead of list for str.startswith.
# rem = ['remove', 'rem-ove', 'rem ove']
rem = ('remove', 'rem-ove', 'rem ove')
with open('DB12', 'r') as inputFile, open('DB12_NEW', 'w') as outputFile:
for line in inputFile.readlines():
if not line.startswith(rem):
outputFile.writelines(line)

Currently you check if the line starts with the a word from the remove list one at a time. For example:
If the line starts with "rem ABCDF..." and in your loop you check if the line starts with 'remove' then your if-statement returns false and writes the line in your outputfile.
You could try something like this:
remove = ['remove', 'rem-ove', 'rem', 'rem ove' ...... 'n']
inputFile = open(r"C:\DB12", "r")
outputFile = open(r"C:\DB12_NEW", "w")
for line in inputFile.splitlines():
if not any(line.startswith(i) for i in remove):
outputFile.write(line)
The any keyword only returns False if all elements are also False.

Sometimes this could be caused by leading/trailing spaces.
Try stripping off empty spaces using strip() and check.
rem = [x.strip() for x in rem]
lines = [line.strip() for line in lines]

Why is my if statement not working and just outputting the else, everything works till there? [duplicate]

In Python, calling e.g. temp = open(filename,'r').readlines() results in a list in which each element is a line from the file. However, these strings have a newline character at the end, which I don't want.
How can I get the data without the newlines?

You can read the whole file and split lines using str.splitlines:
temp = file.read().splitlines()
Or you can strip the newline by hand:
temp = [line[:-1] for line in file]
Note: this last solution only works if the file ends with a newline, otherwise the last line will lose a character.
This assumption is true in most cases (especially for files created by text editors, which often do add an ending newline anyway).
If you want to avoid this you can add a newline at the end of file:
with open(the_file, 'r+') as f:
f.seek(-1, 2) # go at the end of the file
if f.read(1) != '\n':
# add missing newline if not already present
f.write('\n')
f.flush()
f.seek(0)
lines = [line[:-1] for line in f]
Or a simpler alternative is to strip the newline instead:
[line.rstrip('\n') for line in file]
Or even, although pretty unreadable:
[line[:-(line[-1] == '\n') or len(line)+1] for line in file]
Which exploits the fact that the return value of or isn't a boolean, but the object that was evaluated true or false.
The readlines method is actually equivalent to:
def readlines(self):
lines = []
for line in iter(self.readline, ''):
lines.append(line)
return lines
# or equivalently
def readlines(self):
lines = []
while True:
line = self.readline()
if not line:
break
lines.append(line)
return lines
Since readline() keeps the newline also readlines() keeps it.
Note: for symmetry to readlines() the writelines() method does not add ending newlines, so f2.writelines(f.readlines()) produces an exact copy of f in f2.

temp = open(filename,'r').read().split('\n')

Reading file one row at the time. Removing unwanted chars from end of the string with str.rstrip(chars).
with open(filename, 'r') as fileobj:
for row in fileobj:
print(row.rstrip('\n'))
See also str.strip([chars]) and str.lstrip([chars]).

I think this is the best option.
temp = [line.strip() for line in file.readlines()]

temp = open(filename,'r').read().splitlines()

My preferred one-liner -- if you don't count from pathlib import Path :)
lines = Path(filename).read_text().splitlines()
This it auto-closes the file, no need for with open()...
Added in Python 3.5.
https://docs.python.org/3/library/pathlib.html#pathlib.Path.read_text

Try this:
u=open("url.txt","r")
url=u.read().replace('\n','')
print(url)

To get rid of trailing end-of-line (/n) characters and of empty list values (''), try:
f = open(path_sample, "r")
lines = [line.rstrip('\n') for line in f.readlines() if line.strip() != '']

You can read the file as a list easily using a list comprehension
with open("foo.txt", 'r') as f:
lst = [row.rstrip('\n') for row in f]

my_file = open("first_file.txt", "r")
for line in my_file.readlines():
if line[-1:] == "\n":
print(line[:-1])
else:
print(line)
my_file.close()

This script here will take lines from file and save every line without newline with ,0 at the end in file2.
file = open("temp.txt", "+r")
file2 = open("res.txt", "+w")
for line in file:
file2.writelines(f"{line.splitlines()[0]},0\n")
file2.close()
if you looked at line, this value is data\n, so we put splitlines()
to make it as an array and [0] to choose the only word data

import csv
with open(filename) as f:
csvreader = csv.reader(f)
for line in csvreader:
print(line[0])

reading .txt file in python

I have a problem with a code in python. I want to read a .txt file. I use the code:
f = open('test.txt', 'r') # We need to re-open the file
data = f.read()
print(data)
I would like to read ONLY the first line from this .txt file. I use
f = open('test.txt', 'r') # We need to re-open the file
data = f.readline(1)
print(data)
But I am seeing that in screen only the first letter of the line is showing.
Could you help me in order to read all the letters of the line ? (I mean to read whole the line of the .txt file)

with open("file.txt") as f:
print(f.readline())
This will open the file using with context block (which will close the file automatically when we are done with it), and read the first line, this will be the same as:
f = open(“file.txt”)
print(f.readline())
f.close()
Your attempt with f.readline(1) won’t work because it the argument is meant for how many characters to print in the file, therefore it will only print the first character.
Second method:
with open("file.txt") as f:
print(f.readlines()[0])
Or you could also do the above which will get a list of lines and print only the first line.
To read the fifth line, use
with open("file.txt") as f:
print(f.readlines()[4])
Or:
with open("file.txt") as f:
lines = []
lines += f.readline()
lines += f.readline()
lines += f.readline()
lines += f.readline()
lines += f.readline()
print(lines[-1])
The -1 represents the last item of the list
Learn more:
with statement
files in python
readline method

Your first try is almost there, you should have done the following:
f = open('my_file.txt', 'r')
line = f.readline()
print(line)
f.close()
A safer approach to read file is:
with open('my_file.txt', 'r') as f:
print(f.readline())
Both ways will print only the first line.
Your error was that you passed 1 to readline which means you want to read size of 1, which is only a single character. please refer to https://www.w3schools.com/python/ref_file_readline.asp

I tried this and it works, after your suggestions:
f = open('test.txt', 'r')
data = f.readlines()[1]
print(data)

Use with open(...) instead:
with open("test.txt") as file:
line = file.readline()
print(line)

Keep f.readline() without parameters.
It will return you first line as a string and move cursor to second line.
Next time you use f.readline() it will return second line and move cursor to the next, etc...

Removing all spaces in text file with Python 3.x

So I have this crazy long text file made by my crawler and it for some reason added some spaces inbetween the links, like this:
https://example.com/asdf.html (note the spaces)
https://example.com/johndoe.php (again)
I want to get rid of that, but keep the new line. Keep in mind that the text file is 4.000+ lines long. I tried to do it myself but figured that I have no idea how to loop through new lines in files.

Seems like you can't directly edit a python file, so here is my suggestion:
# first get all lines from file
with open('file.txt', 'r') as f:
lines = f.readlines()
# remove spaces
lines = [line.replace(' ', '') for line in lines]
# finally, write lines in the file
with open('file.txt', 'w') as f:
f.writelines(lines)

You can open file and read line by line and remove white space -
Python 3.x:
with open('filename') as f:
for line in f:
print(line.strip())
Python 2.x:
with open('filename') as f:
for line in f:
print line.strip()
It will remove space from each line and print it.
Hope it helps!

Read text from file, remove spaces, write text to file:
with open('file.txt', 'r') as f:
txt = f.read().replace(' ', '')
with open('file.txt', 'w') as f:
f.write(txt)
In #Leonardo Chirivì's solution it's unnecessary to create a list to store file contents when a string is sufficient and more memory efficient. The .replace(' ', '') operation is only called once on the string, which is more efficient than iterating through a list performing replace for each line individually.
To avoid opening the file twice:
with open('file.txt', 'r+') as f:
txt = f.read().replace(' ', '')
f.seek(0)
f.write(txt)
f.truncate()
It would be more efficient to only open the file once. This requires moving the file pointer back to the start of the file after reading, as well as truncating any possibly remaining content left over after you write back to the file. A drawback to this solution however is that is not as easily readable.

I had something similar that I'd been dealing with.
This is what worked for me (Note: This converts from 2+ spaces into a comma, but if you read below the code block, I explain how you can get rid of ALL whitespaces):
import re
# read the file
with open('C:\\path\\to\\test_file.txt') as f:
read_file = f.read()
print(type(read_file)) # to confirm that it's a string
read_file = re.sub(r'\s{2,}', ',', read_file) # find/convert 2+ whitespace into ','
# write the file
with open('C:\\path\\to\\test_file.txt', 'w') as f:
f.writelines('read_file')
This helped me then send the updated data to a CSV, which suited my need, but it can help for you as well, so instead of converting it to a comma (','), you can convert it to an empty string (''), and then [or] use a read_file.replace(' ', '') method if you don't need any whitespaces at all.

Lets not forget about adding back the \n to go to the next row.
The complete function would be :
with open(str_path, 'r') as file :
str_lines = file.readlines()
# remove spaces
if bl_right is True:
str_lines = [line.rstrip() + '\n' for line in str_lines]
elif bl_left is True:
str_lines = [line.lstrip() + '\n' for line in str_lines]
else:
str_lines = [line.strip() + '\n' for line in str_lines]
# Write the file out again
with open(str_path, 'w') as file:
file.writelines(str_lines)